1. Field of the Invention
This invention relates to a rotary coupling for connecting a control device housing to a support arm or an elbow of a support arm system, said rotary coupling comprising a rotating ring fixedly connected to the control device housing and partially rotatable in relation to a coupling piece connected to the support arm or the elbow.
2. Description of Prior Art
Such a rotary coupling is known from German Patent Disclosure P 40 33 747.2. This known rotary coupling permits pivoting of the control device housing around a vertical pivot axis. The selected pivot position can also be locked in. Pivoting is limited to 360.degree., since supply lines are fed through the rotary coupling.
The disadvantage of such rotary couplings is that the pivot axis no longer extends vertically because of insufficient twist rigidity of the support arm system, particularly with heavy control devices. The result is that the control device housing takes up a more or less canted position which, depending on the pivot direction, also is additionally upwardly changed.